sperry



R43, E. A. SPERRY I y WIRELESS REPEATER SYSTEll Origthal Filed larch 12.1920 :s Sheets-Sheet; 1

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- E. A. SPERRY wmanass urn/ma SYSTEM origins; Filed larch 12. 1920SlSheets-Shet. s

I j anbe ntoz I /5 5 /VEKflSPE/FRX out me Reiaued a. 7, 1924.

PATENT OFFICE.

ELHEB A. SPERBY, OF BROOKLYN, NEW YORK, ASSIGNO'R TO THE SPERRYGYBOSOOPE I COMPANY, OF BROOKLYN, YORK, A CORPORATION OF NEW YORK.

WIRELESS nnrmrnn SYSTEM.

Original No. 1,428,507, dated September 5, 1822, Serial No. 365,144,111Karel: 12, 1920. Application for reissue filed February 6,

To all whom it may concern:

Be it known that I. ELMER A. SPERRY, a citizen of the United States ofAmerica, residing at 1505, Albemarle Road, Brooklyn,

5 New York, in the county of Kings and State of New York, have inventedcertain new and useful Improvements in Wireless Repeater Systems. ofwhich the followingis a specification.

This invention relates to means forautomatically transmitting thereadings of an indicatin member by wireless to a distant point. yinvention is particularly useful in automatically transmitting bywireless to an aircraft or other distant point the read ings of acompass, firecontrol instrument, or other indicator on board a ship,whereby the ships heading or the bearing of a taret observed from theship may be constanty communicated to such distant point. Such a systemhas especial uses in the aerial ordnance control for heavy guns wherethe target is only visible from alrplanes, which signal to the ship orother firing station the bearings of the target. In such a system it isvery desirable that the airplane pilot know the bearing of the ship,guns, etc.

' The chief object of my invention is to provide simple and efiicientnieans-for causing to follow automatically the movements of anotherindicator at a distant point and especially adapted for the useoutlined,

above. Other objects and advanta es will become apparent as thedescription 0 'my invention roceeds.

Referring to the drawings wherein I have shown what I now consider thepreferred forms of my invention 40 Fig. 1 is a diagrammatic view of oneform of transmitting apparatus showing the wirin therefor. I

iig. 2 is a wiring diagram of a receiving apparatus for use inconnection with the transmitting apparatus of Fig. 1.

F ig. 3 is avlew of a detail. Fig. 4 is a wiring diagram showing anoth}r form of receiving apparatus 5 is a wiring diagram showing still anoerform of receiving apparatus.

Fig. 6 is a diagrammatlc view of'oneform of transmitting apparatusshowing the. wiring therefor.

an indicator by means of radiant impulses.

repeater motor 3, I

1924. Serial No. 691,070.

Fig. 7 is a diagrammatic view of a receiving apparatus for use with thetransmitting .celving apparatus of Fig. 7, the top of the containingcasing bein removed.

Fig. 9 is a view in e evation of the parts of the indicating apparatusof Fig. 8, the casing therefor being shown in section.

Figs. 10, 11, and 12 are views of details.

In Fig. 1 I have shown at 1 a conventional indicating instrument, whichma be a rotatable compass card or fire contro indicator. Actuated bythis indicator in a manner well known in theart is a transmitter 2electrically connected with a repeater motor 3. The transmitter 2 andrepeater 3 may be of a type well known in the art, such as shown in thepatent to Elmer A. Sperry SerialNo. 1,296,440, issued March 4, 1919, forrepeater system for gyro-comasses, or in the ap lication for patent-bylmer Meitner, Serial No. 227,680, filed April 10, 1918, for self-settingtransmission system. The repeater motor may be of the six pole typehaving three sets of coils 4, 5, and 6, and an armature 7.

For communicating to a distant point the indications or steps of thearmature of ave provided means whereby, as the respective sets of coilsof repeater 3 are energized, radiant impulses of different frequenciesare sent, each of which frequencies corresponds to one set of coils of arepeater motor 8 at said distant station. Various means may be providedfor transmittin wireless impulses of different frequencies in accordancewith the particular coils ofrepeater 3 which are energized. One form ofsuch means is shown in Fig. 1 and may be constructed substantiall asfollows:

The wire ess sending ap aratusmay be of any conventional type. orinstance, it may comprise a source 9 of E. M. F., connected to aninduction coil 10, to the second ary of which are connected spark gap lland a lurality of inductances 12, 13, and

14 of diflerent values corresponding to dif ferent frequencies of theradiant impulses. q

By means to be described later onlyone of said coilsor inductances at atime is placed coils 12, 13, an

in circuit with the source of E. M. F. Each coil may cooperate with anopen oscillatory circuit consisting of an antenna 12 and earthed coils16 17, and 18'coo1perating with d 14, respective y.

The means for placing coils 12, 13, and 14 successively in circuit withgenerator 9 may take various forms, one of which is shown in Fig. 1, andmore in detail, in Figs. 10, 11, and 12. Said coils are shown eachconnected at one end with a wire 19 "leading to one terminal of theinduction coil Each of said members comprises a double contact portion26 and insulation portions 27 as shown in Fig. 11. The contact portionsof members 20, 21, and 22 are in engagement with sleeve 24 and may be soar-, ranged that when a contact portion of one member passes out fromunder its cooperating brush, a contact portion of the next contact willcome under it corresponding brush, and so on. Sleeve 2: is shownseparated by insulation 29 from shaft23. From the construction abovedescribed it will now be evident that, if shaft 23 berotated to followthe movements of repeater 3, and the contact rtions of members 20, 21and 22 be suitab y arranged with res ct to said shaft one of coils 12,13, an 14 corresponding with the particular set 4, 5, or 6 of the coilsof repeater 3 which is energiied, will be connected in the sendingcircuit. Shaft 23 might be connected directly with the armature ofrepeater motor 3, but owing to the possibility of the motor falling outof step if overloaded, I refer to employ in connection therewith aollow-up system.

As shown in Fig. 1, the aforesaid followup system may comprise a trolley30 rotatable with the armature of repeater motor 3 and connected by aconductor 31 with one terminal of a battery 32 or other source of E. M..F., the other terminal of which source of E. M. F. may be connectedwith one terminal of a motor 33. The other terminal of the motor may beconnected as shown with oppositely wound field coils 34 and 35, whichcoils are connected at their other ends with contact portions 36 and 37respectively of drum 38 fixed to shaft 23 The latter shaft is driven bythe motor 33.

.When armature 7 is at rest trolley 30 rests on a strip of insulationbetween contact portions 36 and 37. When, however, said armature movesin one direction or the other, it'will be evident that current willflowthrough motor 33 and one or the other of field coils 34, 35 therebycausing motor 33to turn insuch direction as to bring the aforesaid stripof insulation again under trolley 30. Shaft 23 and the contact membersmounted thereon are thus turned to follow-up the movements of repeatermotor 3.

For causing a wireless impulse to be sent each time that armature 7moves throu h one ste I may utilize means arrangedsu stantia 1y asfollows: On shaft 23 is a member 38 of insulating material having a lu-vrality of contact segments 39 arrange at suitable portions along itsPeriphery and a conducting hub 40 insulated from shaft 23 by means 'of asleeve 41. 'In the exam is shown, six contact segments 39 are provi edand'are suitably connected to conductin hub 40. The latter is'engaged bya brus 42 connected by conductor 43 to a relay magnet coil 44, whichcoil is connected as shown to one terminal of battery 32. The otherterminal of said battery is shown connected with a brush 45 in engaement with the peri hery of member 38.-

. 46 of re a coil 44 is shown adapted to close a circuit t roughgenerator 9 and induction coil 10 when saidarmature is attracted by saidcoil. Normally the armature is held by a spring 47 in a position inwhich th aforesaid clrcuit is 0 en.

e armature The operation of t e above described a move step-by-step. Asarmature 7 commences to turn throu h'a step, motor 33 is energized toturn sha t 23 through the same step or an is as armature 7 turns.

Preferab y, contact s cuts 39 of member 38 are so arrange that thecircuit through coil-44 is closed at some. oint during the turning ofshaft 23 throu said step or angle and opened again by t e time theturning throu h said step has been completed, since i said circuit isclosed at the exact time that turning through said ste is completed,impulses will be sent continuously until the shaft 23 again commences toturn. At the time the circuit through coil- 44 is closed, the contactportion of the roper one of members 20, 21, and 22 has ee'n broughtunder its cooperating brush so thatthat one of coils 12, 13 and 14 whichcorresponds'with the energized set of repeater coils is connected in thewireless sending circuit.. Consequently an impulse of a frequency corresnding to the aforesaid set of repeater coils will have been sent by thetime shaft .23 has been turned through an angle corresponding to thatthrough which armature 7 has turned. In other words, for each'step ofsaid armature, an impulse corresponding in frequency with the set ofrepeater coils energized is sent. I have shown six contact segments onmem- 1 in the same manner 38, whereby the circuit of thewireless systemwill .be closed six times one revolution of the re ter. It

d is e'vi ent, however, that, where t e re ater has twelve, steps perrevolution, as is the case in the .patent to Sperry aforementioned,twelve contacts might be arranged on member 38, whereby twelve wirelessunpulses r revolutian of the repeater motor would To transmi ed. Ofcourse, if desix contacts, as shown, maybe used even where the repeatermotor has twelve steps, with the result that six impulses per revolutionwould be sent, one for each two ste have shown for purposes ofillustration the wireless transmitting aparatus as controlled indirectlyfrom the master indicating instrument 1 through the medium of one of therepeaters connected with said instrument. It will, however, be obviousthat the shaft 23 can be driven directly by indicator that transmitter2, repeater 3, and the follow-up motor may be omitted from theconnection between said indicator and said shaft.

In Fig. 2 I have shown one form of wireless receiving means adapted tocause the energization of the proper set of coils of a repeater motor .8according to the frequency of the impulses received. Each set 48, 59,and of the repeater coils is shown connected at one end to a commonconductor 51 lead to tone terminal; of a source 52 of E. The sets ofcoils may be connected at their other endsf with conta its 5331154, land55, respectively, 0 certain po ariz re a s which contacts are adapted tobe engaged by the relay armatures 56, 57, and 58. Said armatures areshown connected with the otherterminal of source 52 of E. M. F. Repeatermotor 8 ma be geared or otherwise connected, as is w known in the art,with a repeating indicator 8.

A conventional open oscillatory circuit is shown at 59, coupled withwhich are alurality of closed oscillatory circuits inclu in coils-60,61, and 62. In .circuit with sai coils are suitable detectors ofelectrical oscillations, such detectors being indicated at 63, 64, and65. Coils 60, 61, and 62 cooperate with earthed coils 66, 67, and 68 ofthe 'closedoscilla aforesaid open oscillatory circuit and are eachresponsive to a difl'erent one of the freuencies sent by the transmittermagnet. gloils 69,-70, and 71 are interposed in the tory circuits asshown and are adapted toattract armatures 56, 57, and 58, respectively,to close circuits through the sets of coilcgof the repeater.motor S.

u tionalrepeater motors of the type shown are not polarized, may easilyfall out of step with the transarmatures 57 and as transmitter 2, and

as the armatures of the convenitfollows that the repeater mitter ifnoneof the coils of the re eater are energized, since the armature anindicator movable thereby are then free to take up positions in responseto various external forces. Accordingly I have provided the polarizedrelays shown so that when one of said relays is energized it will closea circuit through the corresponding set of repeater col s and maintainsuch circuit closed until another set of coils is energized. Thearmatures 56, 57, and 58 may be polarized in any suitable andconventional manner. In series'with coil 69 are coils 72 and 73 adapted,when energized, to withdraw 58 from engagement with their respectivecontacts. Likewise, in se-- ries with coil are coils 74 and 75 adaptedto withdraw armatures 56 and 58, while in series with coil'71 are coils76 and 77 ed to withdraw armatures 56 and 57.

The operation of the above described receiving apparatus will now becomeevident. Assuming that an impulse issentofa frequency corresponding torepeater coils 4 and to which coil 60, and detector 63 are responsive,coils 69, 72, and 73 Armature 56 is thus attracted to cause energizationof set 48 of the repeater coils and simultaneously armatures 57 and '58are kept out ofengagementwith their respective con tacts. While theimpulse may be of onl brief duration, will remain in engagement withcontact 53 and kee set 48 of the repeater coils energized. idset of coilwill remain energized until an imlpulse of a difierent freuency issent.v hus, if an impulse of a requenc; to which coil sent, suchfrequency corresponding with repester coils 5, armature 56 will bewithdrawn from eng cut with contact 53 and simultaneously coil 70 willbe energized to attract armature 57 and cause energization of set 49' ofthe repeater coils. If, on the other hand, an impulse of a frequency towhich coil 62 is responsive and corresponding with re ter coils 6 weresent, armature 56 would with contact 53 and simultaneously coil 71 wouldbe energized to attract armature 58 to cause energization of set 50 ofthe repeater coils. In this manner the armature of repeater motor 8 willbe maintained in synchronism. with motor 3 and indicator 1.

In Fig. 4 I have shown an alternative arrangement whe peater rotationmay beobtained at the receiving station. In this case, two six polerepeater motors 78 and 78' ina be so connected with'the shaft 80, whichactuates a suitable indicator, that the coils of one are displacedthirty degrees with respect to the corresponding coils of the other.the: sets of coils of one' motor are energized in between theenergizations of the sets of adapt are energized.

armature 56, being polariz withdrawn from engagement.

61 is responsive is y twelve steps '4 per re- Thus, if

iso

. coilstihe citlhertznotoii, the flhflft so be mov to .s o agrees each.For causing ie coil: of the a oresaid motors to be energized in theproper sequence I have shown connections similar to those shown in Fig.2 exce that six closed osc' circuits, mclu ing coils 81 to 86, naive todifi'erent frequencies, are provid In this case it is obvious thattwelve im ulses per revolution of the repeater 3 sho d be sent, as byprovidingsowelve contact cuts on member 38. A it will be evident, thatsix different frequencies should bev provided in the transmittingapparatus in place of the three. shown, the fre uencies correspondin tosuccessive steps the repeater throug 180. Inasmuch as it will be obviousto those skilled in the art, after inspection of Fig. 1, how sixdilferent inductances inv place ofthree may be connected in thetransmission circuit to obtain the desired results, further illustrationis thought unnecessary.

The sets of coils of repeater 78 I have designated as 87, 88, and 89,while those of repeater 78' are designated as 87', 88', and 89. Asshown, sets 87, 88, and 89 are connected at one end to one terminal ofbattery 79 and the other ends of said sets of coils are connected withcontacts 91, 93, and 95. Sets of coils 87 88', and 89' are likewiseconnected at one end with the aforesaid termicorresponding thereto issent, to whic frequency coil 82 is responsive, the armature whichcooperates with contact 91 will be attracted to close a circuit throughcoils 87 of the repeater 78. If now, coils of re peater motor 3 areenergized while coils 4 remain energized the armature of said motor willmove through thirty, de ees and an impulse of a frequency to which coil83 is r onsive will be sent. A circuit through coi s 87 of motor 78 willthereupon be closed and simultaneousl therewith the circuit throu hcoils 87 0 motor 78 will be broken. I on the other hand, while coils 4remain energized, coils 3 had been energized, animpulse' to which coil81 is responsive would have been sent, which would have resulted in thesimultaneous closing of a circuit through coils 89 of repeater motor 78' and breaking of the circuit through coils 87 of repeater motor 78.The indicator actuated by motors 78 an'd78' may thus be movedstep-by-step in either direction and kept in syn ronism with indicator1.

In Fig. 5 I have shown another form of my invention. In this'figure sets96, 96' and 96" of the coils of repeater motor 97 are shown connected atone end with one terminal of battery 98. The other ends of said coilsare shown connected with relay armatures, 99, 99f,'and 99",respectively, which armatures are adapted to be attracted to engagecontacts connected with theother terminal of battery 98. The armaturesmay be normally biased by springs, as shown, to a position in which therespective circuits through the repeater coils are open. When however,one of the relay coils 100, 100', and 100", isenergized, the corresonding armature will be attracted to close a circuit through thecorresponding repeater coils,

and said armature will remain in its attracted position as lon ascurrent flows through the relay coil. oils 100, 100', and 100" may beconnected inclosed oscillatory circuits including inductances 101, 101',and 101", and coherers 102, 102', and 102", the aforesaid inductancesbein responsive to different frequencies and t e aforesaid oscillatorycircuits cooperating with. open oscillatory circuits comprising antenna103, as shown. Ad'a'cent the coherers are herers. Eac decoherer isarranged to be actuated to render its corr'espondin coherernon-conducting when either 0 'the circuits controlled by the othercoherers and their corresponding relays is-closed. While the decoherersmay assume various forms I deco- I have herein shownthem as respectivelycomprising tappers 105, '105', and 105' which are adapted to beattracted to tap the respective coherers. Magnet coils 106,106, areshown cooperating with tapper 105, the former coil beingin circuit withrepeater coils 96' and the latter with repeater coils 96". Similarlyassociated with tapper 105' are coil 107 in circuit with repeater coils96 and coil 107' in circuit with repeater coils 96", while associatedwith tapper 105" are armature 99 will be attracted to close a circuitthrough repeater coils 96 and that simultaneously tappers 105' and 105"will be attracted to render coherers 102' and 102" non-conducting.Armature 99 will now rcmain attracted until coherer 102 is tapped torender it non-conducting. If, now, coils 5 \of repeater 3 are energized,with the consequent sendin of animpulse of a frequency to which coil101' is responsive, armature rendered non-conductin to How through relaye01 100, and armature current will cease 99 willbe retracted by itsspring to break the circuit through repeater coils 96. If, on

rmeiving apparatus is employed an which brushes en cally connected withthe other hand, coils 6 of repeater 3 had been energized, armature 99"would have been attracted to close a circuit throu h coils 96" and tapers 105 and 105' wou d have "been attracted with the result thatarmature 99 would have been retracted to break the circuit throughrepeater coils 96. Thus, when a set of the coils of repeater 97 isenergized, said set remains energized until the next set is energizedwhereupon the first set is simultaneously deenergiz'ed. It is thusevident that, when synchronism between repeaters 3 and 97 is onceestablished it will be automatically maintained.

In Figs. 6-9, inclusive, I have illustrated another form of m inventionwherein imulses of only two iiferent frequencies need be utilized toreproduce ata distant point the movements of an indicator. In Fig. 6,

the arts corres ndin with similar parts in 1g. 1 are designate by thesame numerals with a prime added. As has been heretofore indicated, itis immaterial what particular form of wireless transmittin and it isevident that various types of apparatus may be utilized. In the .formshown diagrammatically in Fig. 6 difi'erent frequencies may be obtainedby throwing more or less of tuning coil 109 into circuit by actuatingcontact arm 110 to engage one or the'other of contact points 111,1112.For actuatingarm 110 to cause an impulse of the proper frequency to besent at the correct time I may 'emplo apparatus constructed' andarranged su stantially as follows: Cooperating with arm'110, asshown,-are solenoids or magnets 113, 114 which ma be connected at oneend with one termina of battery 32' and at their other ends witharmatures 115, 116, respectively, which armatures are adapted to engagecontacts 117, 118. The latter contacts may be connected asshown withbrushes 119, 120, respectively, the conducting hub ion of a meminsulated from shaft 23'. Member 38' is similar to member 38 of Fig. 3and is provided with conductin ub 40' and insulated each other. I preferto provide twelve segments 39' corresponding with twelve steps perrevolution of the repeater 3', but, of course, the be varied asdesi'red.Adapted to cooperate with the aforesaid contact segments successively isa'brush member 124 which may, be connected in any suitable way with theatr 38' mounted on and segments 39' electrinumber of such segments maytery 32. It follows from the structure above described that, if brush124 be engaged with a segment 39' andif one or the other of armatures115,.116 be attracted to its corresponding contact, a circuit w' v beclosed through the corresponding one of solenoids 113, 114, whereupon animpulse of corresponding frequency will be sent. For

attractin the above mentioned armatuies,

own magnet coils 125, 126, which- I have may be in circuit with fieldcoils 35, 36', respectively. Thus, when motor .33 turns in onedirection, impulses of one frequency may be sent, and, when said motorturns in the other direction, impulses of another frequency may be sent.

From the above described construction it will be apparent that, as longas the repeater motor 3' moves in one dlrection, current will flow throuh one of coils 125,126, thereby attracting t e corresponding armature.If, now, contact segments 39' be properly arranged on the periphery ofmember 83', it will be seen that, during each step of repeater motor 3',a circuit will be closed through one or the other of solenoids 113, 114and an impulse of a frequency corresponding to the direction in whichthe motor turns will be sent. The length of each contact segment 39'may, of course, be

varied as desired in order that impulses of 9 and may indicator throughreduction gearing or otherwise, as is well known in the art. Mountedfixedly on shaft 127 are ratchet wheels 133, 134, having oppositelydirected teeth. Each ratchet wheel is, in the example shown, providedwith twelve teeth corre-.

sponding with twelve steps of repeater motor 3'. For actuating saidratchet wheels I have shown pawls 135, 136, pivoted to the ends ofmembers 137, 138,. respectively, which members are in turn suitablypivoted at their other endsto brackets 139, 140 in casing 131. Springs141, 14 2, interposed between members 137, 138, and casing 131, serve toretract pawls 135, 136 from engagement with the correspondin ratchets.Said pawls are preferably bia by springs 143 144 towa s engagement withthe teeth 0 the correspo ding wheels, and, when retracted, the pawls'maybe engaged with suitable stop members 145, 146, tively. For

' actuating members 137, 138 I have shown Willbe ushedintoelectro-magnets orsolenoids 1 47, 148, the armatures 149, 150 of whichsolenoids are gized, one or the other of pawls 135, 186

gement with the cor- .resp'on ingratchet w eel to turn-shaft 127 onestep in the desired direction. When current-ceases to flow through saidsolenoid, the pawl will he -retracted by the corresponding -one ofsprings 141, 142 into a position out of the path of'its ratchet tively.

tion shown in Figs. 6, 7, 8, and 9 wil 40 wheel; It will now be seenthat ifsolenoids 147, 148 are so connected in the wireless receivingcircuit that, when 1m 'ulses of one frequency are sent, one soleno1 isenergized, and when impulses of another frequency are sent, the othersolenoid is energized, in

dicator 128 willfollow the movements of re ter motor 3. One of thevarious forms w 'ch said circuit connections may assume is shown in'Fig.7.

In Fig. 7, 160 is an antenna and 161 a suitable tunin devim. 151 denotesa suitable detector w ich is influenced by impulses transmitted when,for example, contact arm 110 is in engagement with contact joint 111 and152 is a detector which is influence when contact arm 110 is in engament with contactpoint 112. In circuit with said detectors are shown abattery 153 and relay magnets 154, 155. Controlled through relayarmature 156, are solenoids 147, 148 said solenoids being-shown incircuit with a battery 157, and relay contacts 158, 159, respecinvennowbe ter motor 3' I The operation of the form. of my clear. For each stepof re in one direction one of soenoids 147, 148

and indicator 128 moved through one each time that said solenoid isenergize -Likewise, when repeater motor 3 movesin the reverse direction,the other of solenoids 147, 148 is energized and deenergized during eachstep of the repeater motor, and indicator 128 is thereby moved in thereverse direction. It will thus be apparent that indicator 128 will bemaintained .in ste with re r motor 3'. While a suitab e brake 0 anydesired type will be energiz lustration to show shaft 127 as actuatinganindicator it will evident to those skilled in the art that saidshaftmay transmitter contacts or otherwise actuate a transmitter,

same, and a wireless receiving device a the .wireless a. paratus, may beut' ized inconnection wit my wireless repeater system. Hence no'additional antennae are necessary.

The wireless telephone apparatus could, of

course, 0 crate with impulses of the usual or normal reqggncy andadditional frequencies may easily provided, as, for example, in themanner above disclosed, for the operation of the repeater systeInaocordanoe with the provisions of the patent statutes, I have hereindescribed the principle of operation of my invention, together with theapparatus, which I now consider to represent the best embodiment thereofbut I desire to have it understood that the apparatus shown is onlillustrative and that the invention can e carried out by other means.Also, while it is designed to use the various features and elements inthe combination and relations described, some of these may be alteredand others omitted without interfering with the more general resultsoutlined, and the invention extends to such use.

claim 1. -In combination, a pair of step-by-step repeater motors, andwireless means for causing one of said motors to follow the movements ofthe other of said motors in either of opposite directions.

2. In combination, an indicator, means responsive to radiant im ulses ofa given frequency for moving said indicator] stepby-step in onedirection, and means responsive to radiant impulses of another frequencyfor moving said indicator step-bystep in another direction. may beprovided in connection with shaft reventi accidental movement of saidvshaft w en no impulses are being sent, I have 3. A repeater system foraerial ordnance control comprising the combination with a shipsbearingindicator, of a wireless sending instrument controlled thereby, arepeating indicator adaptedto be mounted on an aircraft, a repeatermotor for actua the a ted to control the energization of said motlir.

4. A repeater system for aerial ordnance control com the combinationwitha ships bearing indicator, of wireless transmission'means c ntrolledthereby, means for patent or the Meitner Havin described my invention,what I ans desire to secure by Letters Patent J automatically v ing thefrequency of the wireless impulse s i n accordance with the direction ofmovement of said indicator, a repeating indicator adapted to be mountedon an aircraft, and ,means responsive to said impulses for actuatingsaid repeating indicator in accordance with the movement of said shipsbearing indicator.

5. A repeater system for? aerial ordnance control comprising thecombination with a ships bearing indicator of a step-by-step repeatermotor controlled thereby, wireless transmission means, follow-up meansinterposed between said motor and said means or effecting the control ofsaid means by said motor, a repeating indicator adapted to be mounted onan ai and means responsive to wirelessimpulses for controlling saidrepeating indicator.

6. A repeater system control comprisin the combination with a shipsbearing in 'cator of wireless transmission means controlled thereby, arepeatfor aerial ordnance ing indicator adapted to be mounted on shiponan aircraft, and means responsive actuated there om, com'pris' board,and means responsive to wireless impulses for' causing movement of saidindir. 7. In combinationwith an indicator, a

' repeater motor controlled thereby, a followup motor controlled by saidrepeater motor, and wireless transmission means controlled by saidfollow-u motor.

8. In combination with a repeater motor,

a follow-u motor controlled thereby, means controlled y said follow-upmotor for transmittin wireless impulses, and means controll by saidfollow-up motor for varying the frequency of said im 'ulses.

9. A repeater system or aerial ordnance control comprisin thecombination with a ships bearing indicator of means controlled therebfor sending wireless im means all h freq f 'd ulses c varym t euencyosai imp a TQM i ndicator adapted to be marmteg sai impulses foractuating said repeating indicator.

10. The combination with a ships gyroscopic compass having atransmitter, of a wireless sendin instrument adapted to be a repeatermotor connected to said transmitter, reversing contacts actuatedthereby, a reversible motor also connected thereto and in circuit bysaid indicator or autematiactuated there therewith and radio-impulsetransmission means actuated by said reversible motor.

11. The combination with a ships gyroscopic compass having atransmitter, of a wireless sending instrument adapted to be actuatedtherefrom, and a wireless receiving instrument adapted tant craft, andactuated from said sending instrument including an indicator showing theheading of the ip on whichsaid compass is mounted.

12. The combination with a ships gyro-' to be located on a dis-' radiotransmitting means controlled by said course responsive means.

14. In combination, a compass mounted upon a dirigible craft andwireless transmitting means centrolled by said compass.

15. A ships heading repeater system dirigible craft comprising with aships bearing in transmittin means controlled thereby,a repeatingindlcator adapted to be mounted on a distant craft, and means re onsiveto for the'combination icator, of wirele wireless impulses sent out bysai transmitting means for causing movement of said indicaton 16. Incombination, a com mounted upon a dirigible craft for in icating headingof the craft, wireless transmitting means controlled by said compass,and means actuated b said wireless meansin accordance with t e headingof the craft.

17. The combination with a ships gyroscopic compass having atransmitter, of a wireless sending oinstrument adapted to m and aremotely-positioned wireless. receiving instrument a apted to beactuated from said sending instrument including an'indicator showing theheadingof the shipon which said compass is moun In testimony whereof Ihereby afiix signature, 7

' ELMER A. SPERRY.

